Idaho uses a flat state income tax of 5.3% in 2026 — the same rate applies to every dollar of taxable income, which makes your paycheck easy to predict. On a $75,000 salary, a single filer pays about $3,975 in state tax and takes home roughly $57,618 a year (about 76.8% of gross) after federal, state, and FICA withholding.

Idaho's 5.3% rate is above the 4.8% average among states that tax wage income. Because the rate is flat, a raise never pushes part of your income into a higher state bracket — every extra dollar is taxed at the same 5.3%, unlike the federal system where higher earnings hit progressively higher brackets.

Remember that FICA is separate from income tax and is not affected by your state. Every worker pays 6.2% for Social Security on the first $184,500 of wages (the 2026 wage base) plus 1.45% for Medicare on all wages. Pre-tax 401(k) and HSA contributions lower your federal and state income tax but do not reduce FICA — a detail that trips up a lot of first-time budgeters.

Idaho moved to a flat income tax after years of graduated brackets and has trimmed the rate more than once since. The state drew heavy in-migration from the West Coast over the past decade — Boise's housing costs rose accordingly — but Idaho's overall tax burden remains moderate, with a grocery tax credit offsetting the fact that Idaho is one of the states that still taxes groceries at the full sales-tax rate.